Magnetic Field Actuation for Explosion-Protected Field Devices
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Solution Overview
Problem
Field devices in automation technology face challenges in achieving explosion protection while maintaining serviceability, as existing pushbutton switches require mechanical or electrical passageways through the housing, compromising compactness and compatibility with different platform designs.
Innovation Solution
A field device with a pushbutton switch arrangement that uses a magnetic field produced by a first element and influenced by a second element, detected by a sensor within the housing, allowing actuation without immediate proximity to the sensor, thus eliminating the need for blind holes and enhancing compactness and platform versatility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pushbutton switches with mechanical or electrical passageways are used, then serviceability is improved, but explosion protection is compromised
Solution Approach 1:
The patent replaces mechanical passageways and electrical contacts with a magnetic field-based actuation system. The pushbutton switch actuates a magnet that moves within a blind hole, influencing a Hall sensor through magnetic field changes without requiring mechanical or electrical connections through the housing wall, thus maintaining explosion protection while enabling serviceability.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the pushbutton actuator and the sensor. The magnet serves as a mediator that transmits actuation information through the housing wall via magnetic field influence, eliminating the need for direct mechanical or electrical passageways while maintaining functional connectivity.
2Ease of operation
If blind holes are used for pushbutton actuation, then information input is enabled, but device compactness is reduced
Solution Approach 1:
The patent utilizes the third dimension (depth of the blind hole) to accommodate the magnet's movement path. The magnet moves axially within the blind hole rather than requiring lateral space, allowing compact planar dimensions while still providing the necessary actuation stroke for reliable pushbutton operation.
Solution Approach 2:
The patent nests the magnet and spring mechanism within the blind hole of the housing. The actuating element with the magnet is positioned within the blind hole, and the return spring is nested within the same space, efficiently utilizing the available volume without protruding beyond the housing exterior.
3Object-affected harmful factors
If elastic housing exterior is used for pushbutton actuation, then electromagnetic compatibility is improved, but explosion protection is compromised
Solution Approach 1:
The patent replaces the elastic housing exterior mechanism with a magnetic field-based actuation system. Instead of using an elastic layer that deforms to actuate switches, the patent uses a magnet moving within a rigid housing, actuated by a pushbutton, maintaining both electromagnetic compatibility and explosion protection through the magnetic field intermediary.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables reliable and compact information input within the field device, meeting explosion protection standards and allowing for various platform designs without compromising electromagnetic compatibility or increasing the device's size.
Implementation Method 1
a first element arranged rigidly on the housing for producing a magnetic field; located on the outer surface of a wall of the housing, an actuating element, which is arranged movably relative to the first element, and which can assume at least a home position and a switching position, wherein the actuating element includes a second element for influencing the magnetic field of the first element
Implementation Method 2
a sensor located in the interior of the housing for registering at least one component of the magnetic field reigning in the sensor
Data Source
AI summary
The invention relates to a field device for automation engineering having a housing, wherein the housing has at least one associated pushbutton switch. Operation of the pushbutton switch is detected, according to the invention, inside the housing without the presence of mechanical or electrical passageway through the wall of the housing. For this, the housing does not need to have a blind hole or an inwardly directed depression. This is achieved by a rigid arrangement of a first element for producing a magnetic field on the outer wall of the housing. By means of interaction with a second element for influencing the magnetic field of the first element, which is arranged in an operating element, a variable magnetic field is produced inside the housing. This magnetic field is sensed by a sensor. On the basis of the alteration in the magnetic field, the sensor can determine whether the pushbutton switch is currently being operated.